(1) Where a person is acquiring or proposing to acquire shares in a public company, it is not lawful for that company, or a company that is a subsidiary of that company, to give financial assistance directly or indirectly for the purpose of the acquisition before or at the same time as the acquisition takes place.”

The next section, 679, bans subsidiaries from doing the same - ie Barclays Bank would not be allowed to lend the money any more than Barclays Group.

Assistance by public company for acquisition of shares in its private holding company.

(1) Where a person is acquiring or proposing to acquire shares in a private company, it is not lawful for a public company that is a subsidiary of that company to give financial assistance directly or indirectly for the purpose of the acquisition before or at the same time as the acquisition takes place.

Part of the problem analysising the cash-call is that it was expensive and involved a raft of complex instruments as well as different individuals and sovereign funds.

However, the Companies Act is also pretty comprehensive in capturing all sorts of different definitions of “financial assistance.”

The clarity of the law makes the allegation about the existence of the loan even more baffling. Why would Barclays take the risk? And Qatar, with 80pc of the world’s gas reserves, isn’t exactly short. No doubt Barclays will clarify it all today.

UPDATE: Barclays has changed its mind and said there will be no further up-date from its earlier comment: “Both the FSA and SFO investigations are on-going, and as such we are unable to comment further.”